Lactarius indigo

Spores are translucent ( hyaline ) , elliptical or nearly spherical . Its dimensions range from 7 to 9 microns long and between 5.5 and 7.5 of ancho.8 Through scanning electron microscope crosslinks can be observed on the surface of the holding four esporas.11 The basidia spore between 37 and 45 microns long and 8 to 10 of ancho.12 the pleurocistidios are between 40 and 56 microns long and between 6.4 and 8 wide, and spindle-shaped , with very narrow apex. The cheilocistidios are abundant , and its dimensions ranging from 40 to 45.6 microns long and 5.6 to 7.2 ancho.11

reference: Fries EM. (1836–38). «Seu synopsis hymenomycetum». Epicrisis systematis mycologici (Upsaliae) (en latin): 341.

Without a doubt, this is one of the most striking agarics seen anywhere. When fresh and moist, the intense blue color really stands out; even the latex is blue. Found throughout eastern North America, it is distributed south to southern Colombia where it is associated with Quercus humboldtii. Associates in Costa Rica include Q. seemannii, Q. copeyensis, Q. oocarpa, Q. oleoides, Q. corrugata and Q. costaricensis. There is a form (or perhaps a distinct taxon), found near Palo Verde in the northern Talamancas, that has narrow crowded lamellae, an azonate pileus and smaller stature (image at lower left). This Lactarius is another example of the North Temperate heritage of mycorrhizal agarics in neotropical oak forests.
http://www.nybg.org/bsci/res/hall/indigo...